Move safe_strerror to common/

This patch moves safe_strerror from the gdb/{posix,mingw}-hdep.c files
to the respective common/{posix,mingw}-strerror.c files.  This is a
preparation for the next patch, which shares a common code (to disable
address space randomization when creating a new inferior).

The patch has been regtested on Fedora 20 x86_64, and no regressions
were found.

gdb/ChangeLog
2015-01-15  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (ALLDEPFILES): Including common/mingw-strerror.c and
	common/posix-strerror.c.
	(posix-strerror.o): New rule.
	(mingw-strerror.o): Likewise.
	* common/common-utils.h (safe_strerror): Move prototype to here,
	from utils.h.
	* common/common.host: New file.
	* common/mingw-strerror.c: Likewise.
	* common/posix-strerror.c: Likewise.
	* configure: Regenerated.
	* configure.ac: Source common/common.host.  Add variable
	common_host_obs to gdb_host_obs.
	* contrib/ari/gdb_ari.sh: Mention gdb/common/mingw-strerror.c and
	gdb/common/posix-strerror.c when warning about the use of
	strerror.
	* mingw-hdep.c (safe_strerror): Remove definition; move it to
	common/mingw-strerror.c.
	* posix-hdep.c (safe_strerror): Remove definition; move it to
	common/posix-hdep.c.
	* utils.h (safe_strerror): Remove prototype; move to
	common/common-utils.h.

gdb/gdbserver/ChangeLog
2015-01-15  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (posix-strerror.o): New rule.
	(mingw-strerror.o): Likewise.
	* configure: Regenerated.
	* configure.ac: Source file ../common/common.host.  Initialize new
	variable srv_host_obs.  Add srv_host_obs to GDBSERVER_DEPFILES.

4 files changed, 144 insertions, 0 deletions

diff --git a/gdb/common/common-utils.h b/gdb/common/common-utils.h
index f110924..60aa030 100644
--- a/gdb/common/common-utils.h
+++ b/gdb/common/common-utils.h
@@ -62,4 +62,10 @@ int xsnprintf (char *str, size_t size, const char *format, ...)
 
 char *savestring (const char *ptr, size_t len);
 
+/* The strerror() function can return NULL for errno values that are
+   out of range.  Provide a "safe" version that always returns a
+   printable string.  */
+
+extern char *safe_strerror (int);
+
 #endif
diff --git a/gdb/common/common.host b/gdb/common/common.host
new file mode 100644
index 0000000..8a83882
--- /dev/null
+++ b/gdb/common/common.host
@@ -0,0 +1,36 @@
+# Common object files to include for each host.
+#
+# Copyright (C) 2015 Free Software Foundation, Inc.
+#
+# This file is part of GDB.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Map host triplet into the common object files to be included by
+# GDB/gdbserver.  This is invoked from the autoconf generated
+# configure script.
+
+# This file sets the following shell variables:
+#  common_host_obs		host-specific .o files to include when building
+#  				GDB/gdbserver
+
+case "${host}" in
+
+*-mingw*)	common_host_obs=mingw-strerror.o
+		;;
+*)
+		common_host_obs=posix-strerror.o
+		;;
+
+esac
diff --git a/gdb/common/mingw-strerror.c b/gdb/common/mingw-strerror.c
new file mode 100644
index 0000000..c62c42d
--- /dev/null
+++ b/gdb/common/mingw-strerror.c
@@ -0,0 +1,64 @@
+/* Safe version of strerror for MinGW, for GDB, the GNU debugger.
+
+   Copyright (C) 2006-2015 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+
+#include <windows.h>
+
+/* Implementation of safe_strerror as defined in common-utils.h.
+
+   The Windows runtime implementation of strerror never returns NULL,
+   but does return a useless string for anything above sys_nerr;
+   unfortunately this includes all socket-related error codes.
+   This replacement tries to find a system-provided error message.  */
+
+char *
+safe_strerror (int errnum)
+{
+  static char *buffer;
+  int len;
+
+  if (errnum >= 0 && errnum < sys_nerr)
+    return strerror (errnum);
+
+  if (buffer)
+    {
+      LocalFree (buffer);
+      buffer = NULL;
+    }
+
+  if (FormatMessage (FORMAT_MESSAGE_ALLOCATE_BUFFER
+		     | FORMAT_MESSAGE_FROM_SYSTEM,
+		     NULL, errnum,
+		     MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT),
+		     (LPTSTR) &buffer, 0, NULL) == 0)
+    {
+      static char buf[32];
+      xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
+      return buf;
+    }
+
+  /* Windows error messages end with a period and a CR-LF; strip that
+     out.  */
+  len = strlen (buffer);
+  if (len > 3 && strcmp (buffer + len - 3, ".\r\n") == 0)
+    buffer[len - 3] = '\0';
+
+  return buffer;
+}
diff --git a/gdb/common/posix-strerror.c b/gdb/common/posix-strerror.c
new file mode 100644
index 0000000..119fcf6
--- /dev/null
+++ b/gdb/common/posix-strerror.c
@@ -0,0 +1,38 @@
+/* Safe version of strerror for POSIX systems for GDB, the GNU debugger.
+
+   Copyright (C) 2006-2015 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+
+/* Implementation of safe_strerror as defined in common-utils.h.  */
+
+char *
+safe_strerror (int errnum)
+{
+  char *msg;
+
+  msg = strerror (errnum);
+  if (msg == NULL)
+    {
+      static char buf[32];
+
+      xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
+      msg = buf;
+    }
+  return (msg);
+}